Question

Calculate the percent error that would be caused in the A280 nm reading of BSA at 1 mg/mL in the presence of RNA at 30 micrograms/mL. Calculate the effect on the A280/A260 ratio.

Answer 1

Percentage error when 1mg/ml BSA is contaminated with 30ug/ml RNA.

The percentage error is calculated by the following

% Error = [(Experimental value - Theoretical Value) / Theoretical Value] * 100

In the above sum, the experimental concentration of BSA is 1.03mg/ml (concentration of RNA Aand BSA) and Theoretical concentration of BSA is 1 mg/ml

% Error = [1.03 - 1 / 1 ] *100

= 3%

Calculate the effect on the A280/A260 ratio.

A280 is measured as 1mg/ml

A260 is measured as 0.03mg/ml (converting ug in mg)

280/260 ratio = 1/0.3 = 33

The 280/260 ratio is high than desirable ration, the ratio is high due to RNA contamination in protein.